For enhanced safety, the front and rear seat shoulder belts of the Mercedes E-Class Sedan have pretensioners to tighten the seatbelts and eliminate dangerous slack in the event of a collision and force limiters to limit the pressure the belts will exert on the passengers. The BMW 3 Series Sedan doesn’t offer pretensioners for its rear seat belts.
For enhanced safety, the front seat shoulder belts of the Mercedes E-Class Sedan are height-adjustable to accommodate a wide variety of driver and passenger heights. A better fit can prevent injuries and the increased comfort also encourages passengers to buckle up. The BMW 3 Series Sedan doesn’t offer height-adjustable seat belts.
To provide maximum traction and stability on all roads, All-Wheel Drive is standard on the E-Class Sedan. But it costs extra on the 3 Series Sedan.
Earlier warning of stopped traffic, traffic signals, dangerous road conditions, weather, or accidents, can keep driver's safer and prevent crashes. The E-Class Sedan has Car-to-X Communication, a system that seamlessly communicates important warnings to the driver about impending danger, if they're available. The 3 Series Sedan doesn’t offer a system that can receive automated systems from infrastructure or other vehicles.
The E-Class Sedan has a standard blind spot warning system that uses sensors to alert the driver to objects in the vehicle’s blind spots where the side view mirrors don’t reveal them. A system to reveal vehicles in the 3 Series Sedan’s blind spot costs extra.
To help make backing out of a parking space safer, the E-Class Sedan has standard Rear Cross-Traffic Alert and Active Brake Assist automatically engages the brakes to help avoid a collision. BMW charges extra for Cross Traffic Warning on the 3 Series Sedan and the 3 Series Sedan’s Cross Traffic Warning does not include automatic braking.
Both the E-Class Sedan and the 3 Series Sedan have standard driver and passenger frontal airbags, front side-impact airbags, driver knee airbags, side-impact head airbags, four-wheel antilock brakes, traction control, electronic stability systems to prevent skidding, crash mitigating brakes, daytime running lights, rearview cameras, driver alert monitors and available lane departure warning systems.